Differential distribution in vitamin D receptor gene variants and expression profile in Northeast Brazil influences upon active pulmonary tuberculosis

Tuberculosis is an infectious disease with variable outcomes. This variability is due to host immune capacity in containing the infection process initiated by the Mycobacterium tuberculosis (MTB). Vitamin D is able to modulate a very specific immune response against MTB infection, and its action relies on vitamin D receptor (VDR) binding. Altered VDR forms may compromise vitamin D pathway and proper immune response after MTB infection. Herein we assessed the relationship of five potentially functional polymorphisms from VDR: rs2228570 FokI, rs11568820 Cdx-2, rs2248098, rs1540339 and rs4760648, with tuberculosis susceptibility. The SNP rs4760648 T/T was associated with differential susceptibility to tuberculosis (OR = 2.50, 95%CI = 1.20-5.36, p = 0.01). The SNP rs1540339 presented association to both T allele (OR = 0.55, 95%CI = 0.35-0.88, p = 0.01) and the T/T genotype (OR = 0.404, 95%CI = 0.20 - 0.78, p = 0.005). The FokI T allele was identified as associated to diminished susceptibility (OR = 0.67, 95% CI = 0.45-0.99, p = 0.04) to active TB, as well as T/T genotype (OR = 0.15, 95%CI = 0.04-0.45, p = 9.58 × 10-5). We also performed the expression analyses and observed a down-regulation of VDR in patients (-10.717 FC, p = 8.42e-12), and according to the presence of associated FokI SNP, we observed that the C/T and T/T genotypes presence increases VDR expression (+ 1.25 and + 2.35 FC, p = 0.425 and p = 0.506, respectively). This study shows that vitamin D receptor variants can influence upon pulmonary tuberculosis susceptibility and VDR mRNA levels are decreased in those patients.